Microcontrollers are often used in low power applications to provide control signals to devices in which they are installed (e.g., devices that operate from battery power). Many microcontrollers for low power applications can enter an inactive mode in which the state of the microcontroller can be maintained, but in which the microcontroller does not operate to provide control signals as it does in the active mode. However, such low power microcontrollers use circuits for providing an internal supply voltage that are typically designed to optimize efficiency in either the active more or the inactive mode, as it is difficult to design such circuits for high efficiency in both modes. This can lead to wasting power in either the active or sleep modes, as the circuits are not optimized for efficiency in both.